title: Muscle strength and functional recovery during the first year after THA.
abstract: BACKGROUND
  Patients undergoing total hip arthroplasty (THA) often are satisfied with the decrease in pain and improvement in function they achieve after surgery. Even so, strength and functional performance deficits persist after recovery, but these remain poorly characterized; knowledge about any ongoing strength or functional deficits may allow therapists to design rehabilitation programs to optimize recovery after THA.
  
  
  OBJECTIVE
  The purposes of this study were to (1) evaluate postoperative muscle strength, function, and quality of life during the first year after THA; and (2) compare strength and function in patients 1 year after THA with a cohort of healthy peers.
  
  
  METHODS
  Twenty-six patients undergoing THA were assessed 1, 3, 6, and 12 months postoperatively, and 19 adults with no hip pathology were tested as a control group. Isometric muscle strength (hip flexors, extensors, abductors, knee extensors, and flexors), functional performance (stair climbing, five times sit-to-stand, timed-up-and-go, 6-minute walk, and single-limb stance tests), and self-reported function (Hip Disability and Osteoarthritis Score, SF-36, and UCLA activity score) were compared.
  
  
  RESULTS
  One month after THA, patients had 15% less hip flexor and extensor torque, 26% less abductor torque, 14% less knee extensor and flexor torque, and worse performance on the stair climbing, timed-up-and-go, single-limb stance, and 6-minute walk. Compared with healthy adults, patients 12 months after THA had 17% less knee extensor and 23% less knee flexor torque; however, the functional testing (including stair climbing, five times sit-to-stand, and the 6-minute walk) showed no significant differences with the patient numbers available between individuals undergoing THA and healthy control subjects. SF-36 Physical Component Scores, although significantly improved from preoperative levels, were significantly worse than healthy adults 1 year after THA (p < 0.01).
  
  
  CONCLUSIONS
  Patients experience early postoperative strength losses and decreased functional capacity after THA, yet strength deficits may persist after recovery. This may suggest that rehabilitation may be most effective in the first month after surgery.
authors.affiliation: Physical Therapy Program, University of Colorado, Anschutz Medical Campus, 13121 E 17th Avenue, Mail Stop C244, Aurora, CO, 80045, USA, dana.judd@ucdenver.edu.
authors.forename: Dana L
authors.initials: DL
authors.lastname: Judd
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Dennis
authors.forename: Abbey C
authors.initials: AC
authors.lastname: Thomas
authors.forename: Pamela
authors.initials: P
authors.lastname: Wolfe
authors.forename: Michael R
authors.initials: MR
authors.lastname: Dayton
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Stevens-Lapsley
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000534:rehabilitation; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D003120:Colorado; D004185:Disability Evaluation; D005260:Female; D006621:Hip Joint / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D007537:Isometric Contraction; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000503:physiopathology / Q000601:surgery*; D010808:Physical Examination; D011446:Prospective Studies; D011788:Quality of Life; D020127:Recovery of Function; D011795:Surveys and Questionnaires; D013997:Time Factors; D019415:Torque; D016896:Treatment Outcome